/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode() : val(0), next(nullptr) {}
 *     ListNode(int x) : val(x), next(nullptr) {}
 *     ListNode(int x, ListNode *next) : val(x), next(next) {}
 * };
 */
class Solution
{
public:
    bool isPalindrome(ListNode *head)
    {
        vector<int> list;
        while (head != nullptr)
        {
            list.push_back(head->val);
            head = head->next;
        }
        int front = 0;
        int back = list.size() - 1;
        while (front < back)
        {
            if (list[front] != list[back])
            {
                return false;
            }
            ++front;
            --back;
        }
        return true;
    }
};